Developing and Testing a GPS-Based Steering Control System for an Autonomous All-Terrain Vehicle

Abstract

Abstract. Crush Protection Device (CPD) could potentially decrease the severity of injuries and the number of fatalities in agricultural All-Terrain Vehicle (ATV) rollover crushes. CPD is a passive safety structure that protects the operator in ATV rollover incidents. The effectiveness of CPDs should be evaluated experimentally with an autonomous ATV in order to conduct repeatable and accurate rollover tests. The long-term goal of this study is to evaluate the performance of CPD in experimental ATV rollover accidents using an autonomous ATV which includes speed, brake, and steering control systems. This study aims to implement a Global Positioning System (GPS) based navigation that allows an autonomous ATV to follow a virtual path in the field. The system was designed and installed on a 4x4 Honda FourTrax Rancher ATV that is equipped with an electric power steering (EPS). The autonomous steering system requires three major components: (1) an accurate positioning system, (2) a high-level controller equipped with the path-following feature, and (3) a low-level controller that provides physical steering of the ATV handlebar. The position data was obtained by a Real-Time Kinematic (RTK) Global Navigation Satellite System (GNSS) system. The high-level controller was built based on the estimation algorithm, Extended Kalman Filter (EKF), which allows centimeter accuracy in position. The proportional, integral, derivative (PID) controller with feedback was utilized in the low-level servo controller to precisely turn the EPS motor on the ATV‘s steering shaft. The performance of the GPS-based steering system was examined by calculating the position error of the autonomous ATV operating on a virtual path. By applying an accurate steering control system, repeatable rollover simulations are expected in future field tests.